1. Field of Invention
The present invention relates to a system for thin film deposition, and more particularly to a system for depositing a thin film using a vapor deposition process.
2. Description of Related Art
During material processing, such as semiconductor device manufacturing for production of integrated circuits (ICs), vapor deposition is a common technique to form thin films, as well as to form conformal thin films over and within complex topography, on a substrate. Vapor deposition processes can include chemical vapor deposition (CVD) and plasma enhanced CVD (PECVD). For example, in semiconductor manufacturing, such vapor deposition processes may be used for gate dielectric film formation in front-end-of-line (FEOL) operations, and low dielectric constant (low-k) or ultra-low-k, porous or non-porous, dielectric film formation and barrier/seed layer formation for metallization in back-end-of-line (BEOL) operations, as well as capacitor dielectric film formation in DRAM production.
In a CVD process, a continuous stream of film precursor vapor is introduced to a process chamber containing a substrate, wherein the composition of the film precursor has the principal atomic or molecular species found in the film to be formed on the substrate. During this continuous process, the precursor vapor is chemisorbed on the surface of the substrate while it thermally decomposes and reacts with or without the presence of an additional gaseous component that assists the reduction of the chemisorbed material, thus, leaving behind the desired film.
In a PECVD process, the CVD process further includes plasma that is utilized to alter or enhance the film deposition mechanism. For instance, plasma excitation can allow film-forming reactions to proceed at temperatures that are significantly lower than those typically required to produce a similar film by thermally excited CVD. In addition, plasma excitation may activate film-forming chemical reactions that are not energetically or kinetically favored in thermal CVD.
Other CVD techniques include hot-filament CVD (otherwise known as hot-wire CVD or pyrolytic CVD). In hot-filament CVD, a film precursor is thermally decomposed by a resistively heated filament, and the resulting fragmented molecules adsorb and react on the surface of the substrate to leave the desired film. Unlike PECVD, hot-filament CVD does not require formation of plasma.